public static IAppBuilder UseBasicAuthentication(this IAppBuilder app, BasicAuthenticationOptions options)
 {
     return app.Use<BasicAuthenticationMiddleware>(options);
 }
 public static IAppBuilder UseBasicAuthentication(this IAppBuilder app, string realm, BasicAuthenticationMiddleware.CredentialValidationFunction  validationFunction)
 {
     var options = new BasicAuthenticationOptions(realm, validationFunction);
     return app.UseBasicAuthentication(options);
 }